1. Field of the Invention
This invention concerns a pipe depth locator in general. More specifically, the pipe locator according to this invention is a type that operates to detect an AC signal that emanates from the pipe or pipeline being measured.
2. Description of the Prior Art
A pipe locator has been described in U.S. Pat. No. 3,988,663 issued Oct. 26, 1976 and assigned to Texaco Inc. That patent teaches a locator instrument for manual operation in determining the subterranean location of a pipeline or the like which carries an AC signal thereon. However, while that patent suggested a technique for making a triangulation measurement to determine the depth of a pipe or pipeline beneath the surface, such operation was clearly a manual one. It would involve the moving of a single detection instrument so as to make a determination directionally from at least two locations, with appropriate measurements in relation thereto, so as to be able to compute the location, i.e. depth of the pipeline.
In addition, there is a prior U.S. Pat. No. 3,866,111 which has indicated a single instrument for detecting the output signals from an electromagnetic energy radiating body. It suggests the measurement of the amplitude of signals taken in three coordinate directions at a number of locations. The plots of such amplitudes then indicate the location of the energy radiating body.
Another depth measuring system has been disclosed in a U.S. Pat. No. 3,893,025. However, that system employs a pair of vertically spaced antennas and measures the comparative amplitudes of signals picked-up by these antennas. Then, the ratio of the amplitudes is a measure of the distance to the buried conductive structure.
It is an object of this invention to provide a unitary instrument which is compact and particularly adapted for use in determining the depth of a pipeline or the like, beneath the bottom of a body of water.